Integrate background processing

1. As an interview author,
2. I would like to be able to add background processing https://assemblyline.suffolklitlab.org/docs/components/AssemblyLine/background_assembly support to my interview
3. And avoid having to customize the output to use background assembly

It should include:

1. Disabling the preview screen and replacing with in-line review screen
2. Invoking the background task